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Abstract
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Reaction of chloro(tetraphenylporphyrinato)manganese(III) with tetra-n-butylammonium
hydrogen monopersulfate (n-Bu4NHSO5) in the presence of high ratio of imidazole was followed by
UV-Vis spectroscopy in CH2Cl2 at room temperature. The variation in the UV-vis spectra shows that
the reaction goes through Mn(III), high valent Mn(V) or Mn(IV), Mn(III), low valent Mn(II) and again
Mn(III) complexes. The Mn(III) complex before the addition of n-Bu4NHSO5 could not be reduced to
Mn(II), but Mn(III) complex which was obtained after decay of high valent Mn complexes was reduced to
Mn(II), probably because its spin state is different from the first one. Addition of methanol to the reaction
mixture (in the presence or absence of ferrocene) shows that two high valent Mn complexes [(MnV(TPP)-
(O)(X)] (X = Im- or OMe-) and [MnIV(TPP)(OMe)2] are involved in the course of the reaction. Using
meta-choloroperbenzoic acid instead of (n-Bu4NHSO5) as oxidant showed that reduction of Mn(III) to
Mn(II) is taking place only in the presence of HSO4
-.
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